Fence post driver



Aug. 29, 1961 P. J. IDDINGS FENCE POST DRIVER Filed May 15, 1958 ATTORNEYS a F: 1.. MM {9W1 4 "A" v m W E {U v m. 1 w ad 2 3 V 2 x N z 1... 5 4% m m 11 I 6 a ?J E1 M; g m g z 0%- T C I1 3 2 a 25 10 w 7 m 5 a a w b aJ V o 6 m fi fi% m @w z M w J J h 1 United States Patent 2,998,087 FENCE POST DRIVER Paul J. Iddings, Rte. 1, Sheridan, Wyo.

Filed May 13, 1958, Ser. No. 734,974 12 Claims. (Cl. 175-152) The invention relates to a post driver for driving fence posts, stakes, or piles into the earth. In a broader aspect, the invention relates to a hammer or driving device for imparting blows or forceful impacts to an element to be driven or otherwise hammered.

More specifically, the invention relates to a manually operable fence post driver of the type that includes a guide that fits over the upper, end of a post and is forcibly brought down upon the post to deliver driving impacts thereto. One of the principal features of the present post driver is that it is constructed to deliver more than one blow to the post on each downstroke of the driver, and is further constructed so that the users hands are substantially relieved of shock incidental to the delivery of said blows.

A further feature resides in constructing the post driver so that it is automatically raised after each downstroke to a height sufiicient for the next work stroke, so that the user is only required to apply forceful downward movement to the driver.

It is an object of this invention to provide a post driver that is capable of imparting a plurality of successive impacts to a post or the like with each stroke of the driver.

A further object is to provide a post driver having a plurality of hammer elements and a lost motion connection therebetween, whereby the several hammer elements are successively effective to produce a plurality of impacts with each stroke of the driver.

A still further object is to provide a post driver having a plurality of hammer elements, one of which comprises a guide means and handle for another, and lost motion connection means between the hammer elements to produce a plurality of successive impacts for each stroke of the driver.

A still further object is to provide a post driver having a plurality of hammer elements and lost motion connection means therebetween including an energy storing means, whereby the several hammer elements are successively effective to produce a plurality of impacts with each stroke of the driver, and the energy storage means is effective .to store a portion of the driving force to initiate a movement of the driver upwardly relative to the driven element after the final impact.

Other objects and advantages of the invention, together with certain details of construction and combination of parts, will be apparent from the following detailed description and the appended claims.

In the drawing, wherein for purposes of illustration, a preferred embodiment of this invention is shown,

FIGURE 1 is an elevational view showing the driver mounted upon the upper end of a partially driven fence post;

FIGURE" 2 is a vertical sectional view through the driver, showing the relation of parts at the beginning of impact of one hammer element with the post being driven;

FIGURE 3 is a view similar to FIGURE 2, but showing the relation of parts at the instant the second hammer element becomes effective on the post being driven;

FIGURE '4 is a vertical sectional view through the .driver taken on the line 4-4 of FIGURE 3; and

FIGURE 5 is a horizontal sectional view through the driver taken on the line 55 of FIGURE 4.

Referring to the several figures of the drawing, wherein 2,998,087 Patented Aug. 29, 1961 the same reference numerals are used to designate the same element:

Numeral 10 generally designates the post driver, which includes a first weighted mass or steel hammer element 11. As shown, this hammer element is cylindrical in form and is provided with a lower, flat, force or impact face 12 adapted to engage the element being driven or hammered. The hammer element 11 is provided at its upper end with an upstanding boss 13, the purpose of which will be described hereinafter. A bore 14 extends transversely of the hammer element 11 and receives a pin 15. The pin 15 is longer than the diameter of the hammer element 11 so that its opposite ends project a substantial distance beyond said element, as shown in FIGURE 5, for a purpose explained hereinafter.

The hammer element 11 is adapted to reciprocate within an elongated cylindrical housing or guide tube 20 which may be formed from a piece of 3" diameter steel tubing about 32" long. The lower end of said guide tube is provided with a flaring skirt 21, which facilitates mounting of the guide tube 20 over the end of a post 28 or other object to be driven. The upper end of the guide tube 20 is closed by a steel abutment plate 22, which is fixedly secured, as by welding 22a, to the upper end of the guide tube. The hammer element 11 is mounted in the guide tube 20 with a close sliding fit. A bleed hole or air vent 23 is bored through the fixed plate 22 to prevent the entrapment of any air that might form a cushion between it and the upper end of the movable hammer element 11.

The guide tube 20 is provided with a pair of diametrically opposed elongated slots 24 near the upper end thereof adapted to receive the outer extensions of pin 15. A helical compression spring 27 encircles the boss 13 on the movable hammer 11 and a boss 29 on the fixed plate 22, for a purpose to be explained hereinafter.

In assembling the driver 10, the plate 22 is first welded in place, and the spring 27 and hammer 11 are inserted into the tube 20 in the order named. The hammer 11 is moved against the yielding force offered by the spring 27 to a position in which the bore 14 is aligned with the slots 24 and the pin 15 is then forced into said bore with a drive fit. The drive fit of the pin 15 not only simplifies assembly of the parts, but prevents the pin from becoming loose as a result of vibration and shock when the post driver 10 is in use.

A pair of oppositely disposed, generally U-shaped handles 25 are provided at diametrically opposite sides of the guide tube 20 to manually operate the post driver 10. The lower ends of the handles 25 are welded directly to the guide tube 20 at 25a, while the upper ends of the handles 25- are welded at 25b to a ring 26. The ring 26, in turn, is welded at 26a to the guide tube 20 at a region immediately below the lower end of the slots 24 and reinforces the guide tube 2 0 against out-of-round deformation in said region. The ring 26 is also adapted to serve as an abutment for the extended end portions of the pin 15, so that the force of impact of the pin 15 is taken by said ring rather than by the portions of the tube 20 at the lower end of the slots 24.

In the structure described, the spring 27, aided by the force of gravity, will urge the first or movable hammer element 11 to its lowermost position in which the extremities of pin 15 are engaged with the lower end of slots 24, which serve as stop means limiting downward movement of said hammer element relative to the guide tube 20. In such position, the face 12 of the hammer element 11 is disposed in a plane about 8" from the upper end of the guide tube 20, or at a point corresponding to about A the length of said tube. Upward move ment of the hammer element 11 relative to the guide tube 20 is limited by engagement of boss 13 von hammer element 11 with the boss 29 on the fixed plate 22, as shown in FIGURES 3 and 4 which travel may be about 2% inches. The plate 22 thus serves as an upper stop means for the hammer element 11. It will be noted that the length of the slots 24 is such that the upper end thereof is above the ends of the pin 15 when the hammer element 11 and plate 22 are engaged. This prevents the pin 15 from producing any hammering action against the upper-end of the slots 24.

From the foregoing, it will be seen that the guide tube 20 and handles 25, together with the fixed plate 22, constitute what may be considered a second weighted mass .or hammer element, and that the pin 15 and slots 24 provide a lost motion connection means to permit relative movement between the first hammer element 11 and the second hammer element 20, 22 and 25. The relative masses of the respective hammer elements may be selected as preferred.

In operation, the post driver is positioned with reference to the fence post 28 or other element to be driven with the upper end of the driven element extending into the guide tube 20. Handles 25 are grasped by the user and the post driver 10 is raised a desired distance, about :18 inches or more, above the upper end of the post 28. The post driver is then forcibly brought down against the upper end of the post 28.

FIGURE 2 shows the position of the parts when the first hammer element 11 initially engages the upper end of the post 28 to deliver a blow thereto. The momentum of the first hammer element 11, when it engages the upper end of the post 28, will produce the first impact, and thereafter the downward movement of said hammer element 11 will be stopped. The remaining structure of the post driver, termed herein the Second hammer element, will continue its downward motion until the plate 22 strikes the boss 13, as shown in FIGURES 3 and 4, thereby causing another impact on the upper end of the post to be delivered through the hammer element 11. Between the first and second impacts, spring 27 will be compressed and any aid in the spring chamber will be free to escape from the vent 23 to avoid any significant dashpot or shock absorbing action.

The spring 27 is chosen of such length and resilience characteristics that it is only partially compressed and absorbs a relatively small part of the momentum of the second hammer element so that, after the second impact is produced, the resiliency of the spring and the energy stored therein will cause a rebound of the first hammer element 11 away from the top of the fence post and initiate an upward movement of the post driver that will raise it about 18" relative to the post 28. This reaction is accompanied by a separation of the hammer element 11 from the plate 22 to the extent permitted by the pin and slots 24. Thus, the post driver 10 is automatically raised by the energy stored in the spring 27 during the downstroke of the driver, so that the user merely holds on to the handles 25 after the second impact and permits the driver to rise without hindrance and then manually applies a downward force to the driver to deliver the next two successive blows.

The hammer blows are repeated until the post is driven to the required depth. In the operation of the device, each downstroke of the post driver 10 produces two successive impacts on the top of the fence post 28, which are eifective to quickly drive the post into the ground.

If desired, additional hammer element (not shown), separated by lost motion means of the type shown, can

be provided to produce more than two successive impacts for each driving stroke of the post driver.

While the invention has been disclosed as manually other power fordriving piles or similar objects.

I claim:

1. A post driver, comprising: a first hammer element adapted to directly engage a member to be driven and to deliver an impact thereto, guide means for said hammer element movable relative thereto and including a first stop carried by the guide means directly engaging the first hammer element during a driving operation to limit the travel of said hammer element relative to said guide means in one direction and a second step to limit the travel of said hammer element in an opposite direction relative to the guide means during rebound after a driving operation, said second stop comprising a pin and slotconnection between said hammer element and said guide means, said guide means having mass to form a second hammer element, said first hammer element including a projection engageable with said first stop, energy storing means between said first hammer element and said first stop and surrounding said projection normally urging said hammfiler elements apart while permitting direct impact between said first stop and said projection, whereby a plurality of successive impacts may be delivered to a driven element by a single stroke of the driver, and the energy stored in the energy storing means during impact is released to produce a movement of the driver upwardly relative to the driven element after final impact.

2. A post driver as recited in claim 1, wherein said energy storing means comprises a spring element.

3. A post driver comprising: a tubular member having an open end and a closed end to form a guide to receive an end of a post to be driven; a member slidable within said tubular member adapted to directly engage the post to be driven; said slidable member constituting a first hammer means and said tubular member constituting a second hammer means, said first hammer means being directly engageable with the closed end of the guide; resilient means between the first hammer means and the closed end to urge the first hammer means away from the closed end; and cooperating stop means, carried by said first hammer means and said tubular guide member, to limit movement of the first hammer means away from the closed end, whereby, during a driving operation, the first hammer means directly engages a post to be driven to impart a first impact, and the closed end of the tubular guide element directly engages the first hammer means to impart a second impact to the post.

4. A post driver as recited in claim 3, in which the cooperating stop means comprises a pin carried by one of said hammer means engaging a slot in the other hammer means.

5. A post driver as recited in claim 4, in which the pin is carried by the first hammer means, and the slot is formed in the wall of the tubular member.

6. A post driver as recited in claim 5, including handle means, a ring secured about the tubular member adjacent one end of the slot to form an abutment for the pin, one end of the handle means being connected with said ring, and another end being connected with said tubular member.

7. A post driver as recited in claim 3, in which the tubular member is elongated to surround a substantial portion of the driven element to form a guide means for the driver during impact.

8. A post driver as recited in claim 3, including an abutment plate forming said closed end of the tubular member, said resilientmeans reacting between said first hammer means and said abutment plate.

9. A post driver as recited in claim 8, in which said resilient means comprises a helical spring engaging said abutment plate and one end of said first hammer means.

10. a post driver as recited in claim 9, in which said one end of the-first hammer means includes an upstanding boss adapted to directly engage the abutment plate when the first hammer-means is displaced upon impacting-a driven element.

11. A post driver as recited in claim 10, in which the helical spring surrounds said boss.

12. A post driver as recited in claim 8, in which said abutment plate includes an air bleed opening sufficiently large to prevent the air in said tubular member between said first hammer means and said abutment plate from producing any significant shock-absorbing action.

1,107,976 McCoy Aug. 18, 1914 6 Judd May 24, 1932 Lundgren et a1. Sept. 28, 1954 Clugage Apr. 17, 1956 Yoch Ian. 27, 1959 Green Feb. 3, 1959 FOREIGN PATENTS Australia Mar. 13, 1940 

